Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al.
Steve

Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al.
Steve

Biz WDØHCO wrote:

After 31 years and a bunch of parts in the garage, I am finally building my
dream CW receiver from scratch.

Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage
if doing so would be worth the effort to reduce hum.

Opinions ?

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes up
to 7/8" with a unibit but I think 7/8" is as big as they get.

Thanks

Biz - WDØHCO

A jig-saw should be able to cut a 4 inch dia hole.
There are also drill held hole cutters that have a lathe type cutter on
the end of a rotating arm..Mean looking device when it rotates but it
does a good job..
73 de VE3JUA

Biz WDØHCO wrote:

After 31 years and a bunch of parts in the garage, I am finally building my
dream CW receiver from scratch.

Just wondering if I converted the 6.3 VAC filament voltage to a DC voltage
if doing so would be worth the effort to reduce hum.

Opinions ?

Also I would like to cut a round 4" diameter hole in the 1/8" aluminum front
panel for the speaker grill. Is there a way to do this without a Greenlee
Pneumatic punch? I have a jig saw which I can cut square holes but round
holes are another matter. Is there a better way? I can drill round holes up
to 7/8" with a unibit but I think 7/8" is as big as they get.

Thanks

Biz - WDØHCO

A jig-saw should be able to cut a 4 inch dia hole.
There are also drill held hole cutters that have a lathe type cutter on
the end of a rotating arm..Mean looking device when it rotates but it
does a good job..
73 de VE3JUA

On Wed, 29 Oct 2003 07:42:08 -0800, W7TI wrote:

On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote:

There are also drill held hole cutters that have a lathe type cutter on
the end of a rotating arm..Mean looking device when it rotates but it
does a good job..
_________________________________________________ ________

I have one of these but I would NOT recommend it. Way too hard to
control and dangerous to boot. Use a hole saw instead.

I thought the ones with the rotating arm were intended for use with a
drill press, not for a handheld drill.

There is a lot of torque from that lever arm, and a moment of
inattention could result in serious injury.

A hole saw is far safer with a handheld drill. Make sure you get one
that will work with metal, though, the wood cutting ones only do wood
and some plastics.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

On Wed, 29 Oct 2003 07:42:08 -0800, W7TI wrote:

On Wed, 29 Oct 2003 08:33:36 -0500, Eskay wrote:

There are also drill held hole cutters that have a lathe type cutter on
the end of a rotating arm..Mean looking device when it rotates but it
does a good job..
_________________________________________________ ________

I have one of these but I would NOT recommend it. Way too hard to
control and dangerous to boot. Use a hole saw instead.

I thought the ones with the rotating arm were intended for use with a
drill press, not for a handheld drill.

There is a lot of torque from that lever arm, and a moment of
inattention could result in serious injury.

A hole saw is far safer with a handheld drill. Make sure you get one
that will work with metal, though, the wood cutting ones only do wood
and some plastics.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

Swells8044 wrote:

Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al.
Steve


And use oil or something to keep the Al. from sticking to the teeth.

Bill K7NOM

Swells8044 wrote:

Go to Home Depot get a 4 in.hole saw.They are made for wood but will cut a few
holes in al.
Steve


And use oil or something to keep the Al. from sticking to the teeth.

Bill K7NOM

W7TI writes:

On Tue, 28 Oct 2003 18:38:39 -0600, Biz WDØHCO wrote:

Just wondering if I converted the 6.3 VAC filament voltage to a DC
voltage if doing so would be worth the effort to reduce hum.

Opinions ?

AC will work fine, but here's the key: Don't ground either side of
the 6.3 volt line. Many hum problems are caused by ground loops
where one side of the filament voltage is run through the chassis.
Manufacturers used to do this to save a few pennies by having only
one filament wire. In a mass production situation this can be made
to work, but for one-off design it's easier and better to just keep
the filament voltage isolated from the chassis or anything else.
Use a twisted pair and run it from socket to socket.

If I did this I would put a 0.01 uF capacitor to ground at each
filament pin, to keep RF from propegating through the wires. I would
also put a resistor to ground somewhere in the string to bleed off any
stray leakage current (maybe 1000 ohms or so), otherwise you might get
voltage buildup that could cause problems.

What about an inadvertent short between the cathode and filament?

Allen

W7TI writes:

On Tue, 28 Oct 2003 18:38:39 -0600, Biz WDØHCO wrote:

Just wondering if I converted the 6.3 VAC filament voltage to a DC
voltage if doing so would be worth the effort to reduce hum.

Opinions ?

AC will work fine, but here's the key: Don't ground either side of
the 6.3 volt line. Many hum problems are caused by ground loops
where one side of the filament voltage is run through the chassis.
Manufacturers used to do this to save a few pennies by having only
one filament wire. In a mass production situation this can be made
to work, but for one-off design it's easier and better to just keep
the filament voltage isolated from the chassis or anything else.
Use a twisted pair and run it from socket to socket.

If I did this I would put a 0.01 uF capacitor to ground at each
filament pin, to keep RF from propegating through the wires. I would
also put a resistor to ground somewhere in the string to bleed off any
stray leakage current (maybe 1000 ohms or so), otherwise you might get
voltage buildup that could cause problems.

What about an inadvertent short between the cathode and filament?

Allen